The present invention is related to a traversing mechanism and particularly to an improved traversing mechanism which effects a primary traversing movement of a plurality of strands while maintaining the strands separated, if desired and without destroying the integrity of the strands.
While other applications for the traversing mechanism of the present invention may be found, the traversing mechanism of the present invention is primarily intended for use in the manufacture of continuous glass strands. In this instance, a plurality of continuous glass strands are drawn from a bushing and wound onto packages. The packages of strands are then moved to a chopping operation where the strands are unwound from the package and passed through a chopper which chops the strands into short fiber bundles of a desired length. These fiber bundles are utilized in the reinforcement of plastics, to produce chopped strand mat and for other similar purposes.
For this type of process it is important that the individual strands maintain their integrity during the chopping operation and that the bundles of fibers formed during the chopping operation maintain their integrity. The strands or the short fiber bundles should not break up into individual filaments or fibers. In addition the traversing mechanism should be capable of maintaining the separate strands being wound onto a package spaced relative to each other so that when the strands are chopped they come off the package at the same time but as individual strands rather than as a single strand.
Traversing devices such as the traversing device illustrated in U.S. Pat. No. 3,399,841 issued Sept. 3, 1968 to S. R. Gensen have been developed for the formation of packages with one or more strands. However, due to the continuous contact of the strands with the cylindrical surface of the traversing device of Gensen, the integrity of the strands (the ability of the strand filaments to remain bonded together) is greatly reduced. Consequently, when the strands are chopped, the fiber bundles become fuzzed at the ends or entirely disintegrate into the component filaments thereby making them unsuitable for reinforcement or chopped strand mat. It is thought that the reduction in strand integrity caused by this particular traversing mechanism is caused, at least in part, by forces which are continuously exerted on the strands as they pass over the cylindrical surface of the traverse. These forces tend to separate the filaments of the strands. In addition, binder is removed from the strands as the strands pass over the cylindrical surface of the traverse.
It is an object of the present invention to provide a traversing mechanism which can maintain the strands in spaced-apart relation as they are being traversed and which can maintain the integrity of the strands.
This is accomplished by providing a traversing mechanism which only has point contact with the strands at spaced-apart intervals along the strands. More specifically, the traversing mechanism comprises a plurality of elongate straight elements which are supported in spaced-apart parallel relationship to define a cylindrical pattern. The elements are mounted with the axis of the elongated elements at an oblique angle with respect to the axis of rotation of the traversing mechanism and as the traversing mechanism is rotated the elongate elements make point contact with the strands to move the strands back and forth in a rapid, small amplitude traversing motion.